#include <iostream>
#include <vector>

using namespace std;

class Solution 
{
public:
    void reverseString(vector<char>& s) 
    {
        for(int i = 0; i < s.size() / 2; i++)
        {
            char temp = s[i];
            s[i] = s[s.size() - 1 - i];
            s[s.size() - 1 - i] = temp;
        }
    }
};